Atomic structure of grown-in antiphase boundaries (APB2) in the Fe-28Al-5Cr (at.%) alloy

Thermal grown-in antiphase boundaries (APBs) of the next-nearest neighbour (APB2) type in the Fe-28Al-5Cr (at.%) alloy were studied in the edge-on orientation by means of high resolution electron microscopy. The interfaces are thin and sharp. The domain walls are rugged, small facets (ledges) 0.5–5 nm long situated in the (100) and (111) planes were observed. Two different structures of the APB2 interface with opposite fault vectors were found. Their atomic arrangements are interpreted by contrast simulations, using two models of stacking of the Al and Fe planes in the boundary.